Apache HttpComponents 多线程处理HTTP请求

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 *  this work for additional information regarding copyright ownership.

 *  The ASF licenses this file to You under the Apache License, Version 2.0

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 *      http://www.apache.org/licenses/LICENSE-2.0

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 *  See the License for the specific language governing permissions and

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 * This software consists of voluntary contributions made by many

 * individuals on behalf of the Apache Software Foundation.  For more

 * information on the Apache Software Foundation, please see

 * <http://www.apache.org/>.

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package org.apache.http.examples.client;



import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.impl.conn.PoolingClientConnectionManager;

import org.apache.http.protocol.BasicHttpContext;

import org.apache.http.protocol.HttpContext;

import org.apache.http.util.EntityUtils;



/**

 * An example that performs GETs from multiple threads.

 *

 */

public class ClientMultiThreadedExecution {



    public static void main(String[] args) throws Exception {

        // Create an HttpClient with the ThreadSafeClientConnManager.

        // This connection manager must be used if more than one thread will

        // be using the HttpClient.

        PoolingClientConnectionManager cm = new PoolingClientConnectionManager();

        cm.setMaxTotal(100);



        HttpClient httpclient = new DefaultHttpClient(cm);

        try {

            // create an array of URIs to perform GETs on

            String[] urisToGet = {

                "http://hc.apache.org/",

                "http://hc.apache.org/httpcomponents-core-ga/",

                "http://hc.apache.org/httpcomponents-client-ga/",

                "http://svn.apache.org/viewvc/httpcomponents/"

            };



            // create a thread for each URI

            GetThread[] threads = new GetThread[urisToGet.length];

            for (int i = 0; i < threads.length; i++) {

                HttpGet httpget = new HttpGet(urisToGet[i]);

                threads[i] = new GetThread(httpclient, httpget, i + 1);

            }



            // start the threads

            for (int j = 0; j < threads.length; j++) {

                threads[j].start();

            }



            // join the threads

            for (int j = 0; j < threads.length; j++) {

                threads[j].join();

            }



        } finally {

            // When HttpClient instance is no longer needed,

            // shut down the connection manager to ensure

            // immediate deallocation of all system resources

            httpclient.getConnectionManager().shutdown();

        }

    }



    /**

     * A thread that performs a GET.

     */

    static class GetThread extends Thread {



        private final HttpClient httpClient;

        private final HttpContext context;

        private final HttpGet httpget;

        private final int id;



        public GetThread(HttpClient httpClient, HttpGet httpget, int id) {

            this.httpClient = httpClient;

            this.context = new BasicHttpContext();

            this.httpget = httpget;

            this.id = id;

        }



        /**

         * Executes the GetMethod and prints some status information.

         */

        @Override

        public void run() {



            System.out.println(id + " - about to get something from " + httpget.getURI());



            try {



                // execute the method

                HttpResponse response = httpClient.execute(httpget, context);



                System.out.println(id + " - get executed");

                // get the response body as an array of bytes

                HttpEntity entity = response.getEntity();

                if (entity != null) {

                    byte[] bytes = EntityUtils.toByteArray(entity);

                    System.out.println(id + " - " + bytes.length + " bytes read");

                }



            } catch (Exception e) {

                httpget.abort();

                System.out.println(id + " - error: " + e);

            }

        }



    }



}